Academic Program

Power Management

Power Management

Brown-out Reset Enable (BOREN)

The BOREN configuration setting consists of two individual bits: BOREN1 and BOREN0. The BOREN bit-field resides in CONFIG1.

BOREN allows an MCU RESET to occur if Vdd drops below a preset value. The voltage level precipitating the RESET is determined by the configuration bit BORV.

There are four options for the two BOREN bits:

  1. Brown-out reset is always enabled.
  2. Brown-out-reset is always disabled.
  3. Brown-out reset is enabled when running but disabled when MCU enters SLEEP Mode.
  4. Brown-reset is controlled at run-time by the SBOREN bit of the PCON register.
BOREN Setting Brown-Out RESET Function
  1  1 ON Always enabled
  0  0 OFF Always disabled
  1  0 NSLEEP Enabled while ACTIVE, disabled within SLEEP mode
  0  1 SBODEN controlled by SBOREN bit of PCON Register

 

Example: Disabling Brown-out RESET

 

Brown-out Voltage Level (BORV)

BORV is a single configuration bit residing in CONFIG2.

BORV is only applicable when the Brown-Out Reset (controlled by the BOREN configuration bit) is active.
BORV selects one of two pre-set voltage levels as the Brown-out Reset voltage.

The voltage levels set by BORV are:

BORV Setting Brown-out Voltage
0 L0 1.9 volts
1 HI 2.5 volts

 

The Brown-out Voltage level set by BORV may vary depending on the particular PIC MCU. Check the datasheet for the brown-out voltage options.

Example: Enable Brown-out RESET to always be active and triggered at 2.5V.

Example: Enable Brown-out RESET at 1.9V while MCU is ACTIVE and disable Brown-out in SLEEP mode.

 

Voltage Regulator (VCAPEN - LDO)

The VCAPEN configuration setting consists of two individual bits: VCAPEN1 and VCAPEN0. The VCAPEN bit-field resides in CONFIG2.

For devices with an internal LDO regulator, VCAPEN determines which pin is assigned as the Vcap pin.

The settings for VCAPEN are:

VCAPEN Setting Function
    0 0 RA6 RA6 is assigned as Vcap
    0 1 RA5 RA5 is assigned as Vcap
    1 0 RA0 RA0 is assigned as Vcap
    1 1 OFF Vcap is disconnected from all pins

 

Not all PIC16F1xxx MCUs have an internal LDO regulator. Please refer to the datasheet of the PIC MCU you are using to determine if there is an LDO and what pins are available as Vcap.

Example: Assigning Vcap to RA6

Disabling Vcap functionality

 

Low Voltage Programming (LVP)

LVP is a single configuration bit residing in CONFIG2.

Low Voltage programming entry mode allows PIC16F1xxx MCUs to be programmed with only Vdd. Using LVP eliminates the need to supply a higher than Vdd voltage on MCLR/Vpp.

The settings for LVP are:

LVP Setting Programming Function
  1   ON Enabled
  0   OFF Disabled

 

Example: Disabling EEPROM Reads from External Sources